The invention disclosed herein relates generally to actuator mechanisms for converting two axis pivoting motion to planar motion, and more particularly to an improved joystick controller mechanism utilizing a sliding disc for acutating transducers actuatable by linear motion in response to pivoting control handle motion.
Joystick or two axis control handles are used as switch or valve actuators in a variety of applications in which it is desirable or necessary to have a plurality of independent functions controlled from a single handle. Examples of such applications include controlling the angle and height of blades, scrapers, cutters, etc. on earth and snow moving machinery, controlling various airfoil surfaces on aircraft, controlling cutter position in multi-axis machine tools, and controlling electron beam position in any of a variety of types of electronic instruments. Many other applications also exist, and the types of applications and quantity of joystick controllers used in connection therewith continue to increase.
The proliferation of apparatus requiring joystick controllers has placed increasingly stringent requirements on all features of such controllers. They are required to operate reliably over a long life. At the same time, the manufacture and sale of such controllers is quite competitive. Therefore, it is necessary that any joystick controller used in significant quantities be designed for simple manufacture. Among other things, the cost restriction essentially dictates a design which utilizes a minimum number of easily assembled parts. In general, compliance with this requirement also enhances reliability and maintainability since a simple design with fewer parts is normally less prone to failures, and is easier to repair if failure occurs.
It is also desirable that a joystick controller be designed to accommodate a variety of switches, proportional electronic output devices, and/or valves. For reliability, maintainability, and availability of replacement parts, the switches, etc. should be easily separable from the actuator mechanism, and should be standard commercially available components. Accommodation of such components is faciliatated by maximizing the space in the controller which is uncommitted to other necessary features of the controller such as mechanisms for mounting the handle shaft for pivotal movement, for biasing the handle to a neutral position, and for actuating transducers in response to handle positions. Concurrent with desirability of maximizing uncommitted space, there is a continuing need to reduce the overall size of joystick controllers, and particularly to reduce the depth of such controllers and the distance they extend behind structures on which they are mounted.
A variety of mechanisms for actuating switches or other transducers which are actuatable by linear motion in response to pivoting motion are known. Many of these are specifically designed for and limited to actuation of a single switch at any one time. One type of mechanism includes only a single switch which is actuated in response to pivoting of a shaft in any direction. Such a device is shown in U.S. Pat. No. 2,612,049, issued to A. Koch, Jr. on Sept. 30, 1952. In the Koch actuator, a control stem or shaft has a rigid spacer or disc fixed to one end thereof. Pivoting of the shaft in any direction causes an edge the disc to have a component of motion parallel with the longitudinal axis of the shaft in its neutral position. This motion component is transferred by means of a suitable linkage to a switch operator which is responsive to such motion.
Another type of mechanism is known in which any one of a plurality of switches is actuatable in response to pivoting shaft motion, but only a single switch is actuatable at one time. For example, U.S. Pat. No. 2,984,720, issued to J. Fischer on May 16, 1961, discloses a control unit in which an operating rod member is mounted for pivoting movement, but is confined to pivoting about either of two orthogonal axes by a slotted plate. A separate pivotally supported level is provided for transferring rod motion to each of four switches associated with the four permitted pivoting directions of the control rod. The slotted plate is required to confine the control rod to positions which provide proper interaction with the pivoting levers. Use of the slotted plate, a plurality of separate pivoting levers and other components results in a relatively high parts count and complicated mechanism.
U.S. Pat. No. 3,666,900, issued to R. Rothweiler et al. on May 30, 1972, discloses a joystick controller having a sliding cam which interacts with translating pins adapted to move in a direction parallel with the longitudinal axis of a joystick operator arm in its neutral position. The translating pins function to operate switches of a push button type. The sliding cam is movable along either of two orthogonal axes transverse to the longitudinal axis in response to pivoting of the operator arm. Movement of the arm as transferred to the cam by a ball formed on one end of the arm which fits into a socket in the cam. The cam is configured to interact with a cavity in a housing so as to permit sliding of the cam only along a single axis at a time as necessary to prevent jamming of the cam and translating pins. This design results in a relatively deep configuration and high parts count.
U.S. Pat. No. 3,639,705, issued to W. Rayner on Feb. 1, 1972, discloses a joystick control switch in which a plurality of depressable plunger type switches are actuatable by direct contact with the sides of one end of a pivotally mounted operating lever. Pivoting of the operating lever is confined to predetermined paths by slots in a base plate as necessary to provide proper interaction between the lever and the plungers on the switches.
Certain other switch actuator designs are known which permit actuation of more than a single switch at one time in response to pivoting of a control handle depending on the components of control handle motion. For example, U.S. Pat. No. 2,391,881, issued to M. Clay on Jan. 1, 1946, discloses a crane control system in which an operating lever pivotally supported at one end actuates switches orthogonally arranged around the lever. The lever is fitted with a contact sleeve having a square cross section in the area of the switch operators so as to permit simultaneous actuation of adjacent switches depending on the direction in which the lever is pivoted. Excursion of the lever is limited by a rigid ring to prevent the sleeve from moving laterally beyond the switch locations. This design, in which the switches are located intermediate the ends of the lever, results in a deep configuration in order that the lever present a relatively linear motion to the switches.
U.S. Pat. No. 2,857,485, issued to R. Brooks on Oct. 21, 1958, discloses a multiposition electrical switch utilizing a wobble disc for bridging between a central distribution contact and one or more contacts arranged around the central contact. The wobble disc is pivotally supported by means of a hub on its lower surface which fits within a stationary recess, and is tilted by means of an operating lever having a spring loaded plunger which is received in the socket in the upper disc surface. This design requires complete integration of the electrical contacts and bridging element with the mechanical portions of the device. Thus, it is not adapted to the use of commercially available switches or other components, and cannot be used with proportional output devices.
U.S. Pat. No. 3,835,270, issued to W. Dufresne on Sept. 10, 1974, discloses a joystick control mechanism in which a printed circuit board is attached to one end of a joystick shaft and moves laterally in response to pivotal shaft motion. The board is held against laterally fixed contact elements by means of a spring. Movement of the printed circuit board causes bridging between sets of contacts by conductive paths on the board depending on position of the board. As with the Brooks multiposition switch, this design is not adapted to use of commercially available switches or other components. In addition, its suitability is limited to relatively low level electrical switching and intermittent use due to limitations on the durability of printed circuit board construction and wear caused by sliding operation between the printed circuit paths and contacts.
The applicant has devised a unique actuator motion conversion device which is exceptionally simple in design and utilizes a minimum number of parts. The design is compact and rugged, and is well adapted to accommodate a wide range of standard commercially available switches, proportional electronic output devices, valves and/or other transducers. Finally, the design minimizes the depth of mechanical portions of the actuator and permits mounting of switches, transducers, etc. in a low profile orientation.